基于“肠-肾轴”理论探究痛风雏鹅肠道细菌易位及其免疫激活机制

In goose production, changes in breeding patterns lead to frequent gout in recent years. The excretion disorder of uric acid caused by renal injury is the direct cause of gout in goslings. In previous works, we have found that intestinal flora disorder is significantly related to the deterioration of renal function in goslings, which might be involved in the development of gout. However, the reasons of renal dysfunction caused by intestinal flora disorder is still not clear, and we aim to explore it in this proposal. Based on the theory of “gut-kidney axis”, we expect that intestinal bacteria and their pathogen-associated molecular patterns (PAMPs) may move along the “gut→circulatory system→kidney” pathway and activate immune responses, and this leads to renal injury. Therefore, we plan to carry out the following studies. Firstly, we use high-protein diets to induce gout in goslings and evaluate the relationship between intestinal mucosal barrier function and the changes in renal function. Secondly, we plan to observe the translocation of intestinal bacteria and lipopolysaccharide (LPS) along the “gut→circulatory system→kidney” pathway, evaluate the formations of circulating immune complexes (CIC), and analyzes the activation of TLRs/MyD88/NF-κB pathway induced by bacterial translocation. Thirdly, the bacteria in cecal contents from diseased goslings are cultured to invade intestinal epithelial cells in vitro. We plan to observe the bacterial translocation and immune activation, in particular the activation of TLRs/MyD88/NF-κB pathway, to verify the molecular mechanisms of bacterial translocation and immune activation at the cellular level. The expected results in this project can provide a theoretical basis of the nutritional intervention methods for the preventions of gout in goslings, and facilitate the scientific transformation of waterfowl breeding.

养殖模式改变导致生产中雏鹅痛风频发，肾脏损伤导致的尿酸代谢障碍是此病发生的直接原因。前期研究发现，肠道菌群紊乱与雏鹅肾脏功能恶化显著相关，参与痛风发生，但目前肠内致病因素诱发肾脏损伤的原因尚不清楚。基于“肠-肾轴”理论，我们推测：雏鹅肠道细菌及其病原相关分子模式（PAMPs）可能沿“肠道→循环系统→肾脏”途径易位，激活免疫应答，导致肾脏损伤。为此，拟开展以下研究：1）利用高蛋白日粮诱发雏鹅痛风，评价肠粘膜屏障功能与肾脏损伤的关联。2）观察雏鹅肠道细菌及LPS沿“肠-肾轴”的易位现象，分析循环免疫复合物（CIC）形成及TLRs/MyD88/NF-κB通路激活，研究因易位引发的免疫应答。3）利用病鹅肠道细菌入侵肠上皮细胞模型，观察其细胞层间位移及对TLRs/MyD88/NF-κB通路的影响，从细胞水平验证细菌易位及其免疫激活。项目预期为探索雏鹅痛风的营养干预方案提供理论依据，助力产业科学转型。

养殖模式改变导致生产中雏鹅痛风频发，肾脏损伤导致的尿酸代谢障碍是此病发生的直接原因。团队前期研究发现，肠道菌群紊乱与雏鹅肾脏功能恶化显著相关，参与痛风发生，但目前肠内致病因素诱发肾脏损伤的原因尚不清楚。本项目研究了雏鹅肠道细菌及其病原相关分子模式（PAMPs）沿“肠道→循环系统→肾脏”途径易位，激活免疫应答，导致肾脏损伤的生理过程。为此，主要开展了以下研究：1）利用胶原酶与中性蛋白酶联合消化的方法建立了鹅原代肠上皮细胞培养体系，并从体外和体内两方面研究了PAMPs典型物质LPS基于TLRs/MyD88/NF-κB炎症信号通路诱导的鹅肠道免疫反应的分子机制。2）通过对2017-2019年间多地区痛风雏鹅病例的分析，明确了大肠杆菌和肠球菌导致的细菌感染是导致雏鹅肠-肾损伤的主要原因。3）通过大群试验，利用高蛋白日粮建立了雏鹅痛风发病模型，阐明了痛风雏鹅肠黏膜屏障功能损伤及肠-肾免疫激活的生理机制，解析了肠道微生态失衡沿“肠道→循环系统→肾脏”途径影响肾脏损伤的过程。4）探索了营养调控技术改善雏鹅痛风的作用效果，通过添加发酵饲料、提高日粮纤维水平等途径改善雏鹅肠道微生态，并其对缓解高蛋白日粮诱导的雏鹅肾脏损伤的缓解效果。综上，本项目的顺利开展解析了雏鹅肠-肾互作的生理过程，并为研发防控雏鹅痛风的营养干预技术提供了理论依据，助力水禽产业技术升级和科学转型。